View Compilation Error

0_0_34397961_23785.cpp: In member function 'bool cmp::operator()(const Message&, const Message&)':
0_0_34397961_23785.cpp:12:18: error: 'const struct Message' has no member named 'index'
   else return m1.index>m2.index;
                  ^
0_0_34397961_23785.cpp:12:27: error: 'const struct Message' has no member named 'index'
   else return m1.index>m2.index;
                           ^
0_0_34397961_23785.cpp: In function 'int main()':
0_0_34397961_23785.cpp:28:32: error: 'mag' was not declared in this scope
     cout<<msg.top().name<<" "<<mag.top().para<<endl;
                                ^
0_0_34397961_23785.cpp:34:30: error: expected ';' before ':' token
    cin>>m.name>>m.para>>m.pri:
                              ^